Mesoporous CeO2-Au Catalyst for Mild Oxidative Esterification
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Solution Overview
Problem
Existing methods for synthesizing esters through oxidative esterification of alcohols or aldehydes often require high temperatures, pressures, and energy, leading to environmental pollution and limited application scope.
Innovation Solution
A mesoporous CeO2-loaded Au catalyst is prepared using covalent organic frameworks as a template and cerium nitrate as a cerium source, with HAuCl4 as a gold source and NaBH4 as a reducing agent, allowing for the oxidative esterification of aromatic alcohols under mild conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If high temperature and pressure are used to enable oxidative esterification reaction, then conversion rate is improved, but energy consumption increases and environmental pollution worsens
Solution Approach 1:
The patent changes the reaction parameters from high temperature and pressure to mild conditions (room temperature or slightly elevated temperature, atmospheric pressure) by introducing a novel catalyst system. This parameter change enables the reaction to proceed at lower energy input while maintaining high conversion rates, thus resolving the contradiction between productivity and energy consumption.
Solution Approach 2:
The patent employs a composite catalyst material consisting of Au nanoparticles supported on CeO2 with specific pore structure. This composite material combines the high catalytic activity of Au with the structural stability and oxygen activation capability of CeO2, enabling the reaction to proceed under mild conditions with high conversion, thereby reducing energy consumption while maintaining productivity.
2Productivity
If high temperature is used to achieve high conversion, then reaction efficiency is improved, but environmental pollution increases
Solution Approach 1:
The patent changes the temperature parameter from high temperature to mild conditions, fundamentally altering the reaction conditions to achieve high conversion without the environmental drawbacks of high-temperature processing. This parameter change reduces energy consumption and minimizes harmful emissions while maintaining reaction efficiency.
Solution Approach 2:
The patent uses a heterogeneous catalyst that can be easily separated and reused, replacing the need for high-energy conventional methods. The catalyst material, while requiring initial preparation, eliminates the need for continuous high-temperature operation, thereby reducing overall environmental impact and operational costs.
3Productivity
If homogeneous catalysts are used for oxidative esterification, then conversion rate is improved, but product separation difficulty increases
Solution Approach 1:
The patent inverts the approach by using heterogeneous catalysts instead of homogeneous catalysts. This inversion allows the catalyst to be easily separated from the reaction mixture through filtration or centrifugation, while still achieving high conversion rates. The heterogeneous nature of the catalyst provides both high activity and ease of separation, resolving the contradiction between productivity and operational ease.
4Productivity
If conventional catalysts require special ligands and additives, then catalytic activity is improved, but device complexity increases
Solution Approach 1:
The patent extracts and eliminates the need for complex ligand systems and multiple additives by developing a catalyst based on simple Au nanoparticles on CeO2 support. This simplified composition maintains high catalytic activity while dramatically reducing the complexity of the catalyst system, making it more suitable for industrial application.
Solution Approach 2:
The patent applies local quality by concentrating the active catalytic sites (Au nanoparticles) on the surface of the CeO2 support, particularly within the porous structure. This localized arrangement provides high catalytic activity at the active sites while keeping the overall catalyst composition simple and easy to prepare, resolving the contradiction between productivity and device complexity.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The catalyst achieves high conversion rates (up to 100%) and selectivity (>99%) for synthesizing aromatic esters at room temperature and atmospheric pressure, with the catalyst being recyclable and maintaining activity after multiple cycles.
Implementation Method 1
taking HAuCl4 as a gold source and NaBH4 as a reducing agent, loading Au nanoparticles on the mesoporous CeO2 carrier material by impregnation-reduction method
Implementation Method 2
direct one-pot oxidative esterification of alcohols or aldehydes
Implementation Method 3
loaded Au non-homogeneous catalysts are effective in the direct oxidative esterification
Data Source
AI summary
The present disclosure provides a preparation method of a mesoporous CeO2-loaded Au catalyst, products and applications thereof, and belongs to the technical field of fine organic chemical industry. According to the present disclosure, firstly, COFs material COFs-41 is employed to prepare mesoporous CeO2 carrier material with high specific surface area; then, Au nanoparticles loaded on the surface of mesoporous CeO2 carrier pores are anchored by impregnation-reduction method to produce Au@CeO2 catalyst with high specific surface area; and then, mesoporous Au@CeO2 catalyst with high specific surface area, aromatic alcohols are added to a reactor, anhydrous methanol is used as a solvent, and heating is carried out to react in an atmosphere of atmospheric oxygen for a certain period of time at room temperature, and this catalyst catalyzes the oxidative transesterification of aromatic alcohols for synthesis of aromatic esters in a highly selective manner.